spring 配置log4j问题 求助！！！！

log4j文件
 log4j.appender.stdout=org.apache.log4j.ConsoleAppender
 log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
 log4j.appender.stdout.layout.ConversionPattern=%d %p [%c] - <%m>%n log4j.appender.logfile=org.apache.log4j.RollingFileAppender
 log4j.appender.logfile.File=${sys.root}/WEB-INF/sys.log
 log4j.appender.logfile.MaxFileSize=1024KB
 # Keep three backup files.
 log4j.appender.logfile.MaxBackupIndex=1
 #log4j.appender.logfile.layout=org.apache.log4j.PatternLayout
 log4j.appender.logfile.layout.ConversionPattern=%d %p [%c] - %m%n
web.xml文件 <context-param>
  <param-name>webAppRootKey</param-name>
  <param-value>sys.root</param-value>
</context-param><context-param>
  <param-name>log4jConfigLocation</param-name>
  <param-value>WEB-INF/log4j.properties</param-value>
</context-param> <listener>
  <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
</listener>程序起后运行后 怎么看不到建的sys.log文件啊